Word Equations
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Transcript Word Equations
Word Equations
CH.3.c
Writing Formulas
Reactions formulas represent what
occurs in a chemical reaction
Reactants are the participants in a
chemical reaction
Products are the new compounds
formed as a result of a chemical
reaction
Evidence?
What are the four products that are
evidence of a chemical reaction?
Symbols
Symbols indicate the conditions of a
reaction
indicates the direction of the
reaction
s,l,g
indicate the state of matter
aq
indicates that the solution is
aqueous, dissolved in water
heat
heat is required to react
Writing Equations
A word equation is used to describe a
chemical reaction
Words describe the conditions, the
reactants and the products
You must make sure that the
chemical formula is properly balanced
(the charge)
Steps
Step 1: Highlight the important parts
of the word problem
Step 2: Identify the reactants and
products
Step 3: Write the formulas for the
chemicals
Practice
Zinc and Lead (II) nitrate yield Zinc
nitrate and Lead
Practice
Aluminum bromide and chlorine yield
aluminum chloride and bromine
Practice
Sodium phosphate and calcium
chloride yield calcium phosphate and
sodium chloride
Practice
Potassium chlorate when heated
yields potassium chloride and oxygen
gas
Practice
Aluminum and hydrochloric acid yield
aluminum chloride and hydrogen gas
Practice
Calcium hydroxide and phosphoric
acid yield calcium phosphate and
water
Practice
Copper and sulfuric acid yield copper
(II) sulfate and water and sulfur
dioxide
Practice
Hydrogen and nitrogen monoxide
yield water and nitrogen
Balancing Equations
Now that you have written the
equation, you must balance it.
Yeah!!!
The Law
Law of Conservation of Mass
Law of Definite Proportions
Balancing Equations
Step 1:
Step 2:
side
Step 3:
Step 4:
Write the equation
Count the Atoms on each
Balance the # of atoms
Verify
The Rules
DO NOT TOUCH THE SUBSCRIPTS!!!!!
The Coefficient is the number in front
of the compound formula
Coefficients represent the ratio of
compounds
Similar to the ratio of atoms in a
chemical formula
The trick is . . .
Determine the number of each type
of atom on the reactant and product
sides.
Balance a polyatomic ion as a single
unit if it remains the same on both
sides
When in doubt, double it out
Practice, practice, practice
___H2 + ___O2 => ___H2O
___H3PO4 + ___KOH => ___K3PO4 +
___H2O
____K + ___B2O3 => ___K2O +
___B
____HCl + ____NaOH => ___NaCl +
____H2O
___Na + ___NaNO3 => ___Na2O +
___N2
___C + ___S8 => ___CS2
__Na + ___O2 => ___Na2O2
___N2 + ___O2 => ___N2O5
___H3PO4 + ___Mg(OH)2 =>
___Mg3(PO4)2 + ___H2O
__NaOH + ___H2CO3 => ___Na2CO3 +
___H2O
___KOH + ___HBr => ___KBr +
___H2O